My chair has foam rubber glued to the wood frame and canvas-type material. Staples and foam pulled out ok but left behind large patches and bits of foam. How do I remove the rest of the foam? I scrubbed with a stiff brush and water but could only loosen small particles. Also tried loosening it up with a hot iron and hair dryer, and Sccr aping it off with a scraper and razor blade but none of these methods worked. Any suggestions? Should I just give up and lay down a new foam layer on top of it?